Manufacture of keys



(No Model.)

H. 0. HART.

MANUFA'G-TURE or KEYS. No. 248,095. Patented Oct. 11,1881.

, UNITED STATES PATENT OE-FICE.

HUBERT C. HART, OF UNIONVILLE, ASSIGNOR TO THE RUSSELL 8a ERWIN MANUFACTURING COMPANY, OF NEW BRITAIN, CONNECTICUT. A

MANUFACTURE OF KEYS.

SPECIFICATION forming part of Letters Patent No. 248,095, dated October 11, 1881.

Application filed May 9, 1881.

To all whom it may concer-n:

Be it known that I, HUBERT C. HART, of Unionville, in the county ofHartford and State of Connecticut, have invented certain new and useful Improvements in the Manufacture of Solid Keys, of which thefollowing is a specication.

My invention relates to the manufacture of solid keys,preferably of steel, from a bar specially designed for said manufacture by means of cutting-dies and sWaging-dies; and the objects of my invention are to produce a merchautable bar from which to manufacture solid keys, and to produce said keys at a small cost.

In the accompanying drawings, Figure lis a side elevation of said bar. Fig. 2 is a transverse section ofthe same on line .1: :vof Fig. l. Fig. 3 is a side elevation of the blank as cut from said bar, and Fig. 4 is a side elevation of a finished key-blank.

I first obtain or make a bar of soft steel of any desired length, in the form shown in Figs.

l and 2, which bar can be readily made by roll,

ing in the ordinary manner of making bar steel or iron. As seen by the sectional view, Fig. 2, this bar is provided with ribs a a upon opposite sides, and the part b, upon one 'side of said ribs, is made thick enough forforming the stem of the key, and the part c, at the other side of said ribs, is thinner, so that the shank and bow may be formed therefrom. These ribs are preferably beveled off, as shown, upon that side which faces the thinnest part of the bar. After said bar is obtained I cut it up into blanks, Fig. 3, by means of a die and punch, which cut on the lines indicated by the con- `,tour of said blank. I next strike the blank Fig. 3, when cold,in swinging-dies, which throw or force the stock into the desired form for the finished key-blank, preferably the form shown in Fig. 4, in which tigure d designates the or- 'dinary round stem, e the bit-blank, k the stop,

f the shank, and g the bow. The bow and bit may be nished and shaped in any ordinary manner.

In striking the blank Fig. 3 to form the blank Fig. 4, the portion which is form-ed into the stem d is changed from its square form into (No model.)

the round stem. The bit portion of blank Fig.

3 is -atted and elongated, the square portion 5o at c, Fig. 3, is formed into the rounded stop k, while the shank and bow are compressed and reduced in thickness enough to give them more solidity and a better finish. As in ordinary swaging-dies, some surplus metal, com- Inonly culled a frm is thrown out from the blank during the swagiu g process, which surplus metal is taken off by a trimming-die. The finished key-blank Fig. 4 is represented as thus trimmed.

It' desired, the blank Fig. 4 may be struck a second time in the swaging-die after it has been trimmed.`

All of the above-described operations which are subsequent to the production of the bar are performed when the stock is cold,'and thereby the blank is left smooth and bright as it comes from the swaging-dies, so that it can be polished, by tumbling'or otherwise, at a small expense. quired, so that a solid steel key is produced at a very small cost.

I am naware that a narrow bar of uniform thickness throughout, except the middle portion, which was provided with rounded beads 7 5 upon opposite sides, whereby the bar was specially adapted for cutting key-blanks therefrom with the beads running longitudinally with the key-blanks, is old, and is hereby disclaimed.

I claimA as my invention- The bar Figs. 1 and 2, having ribs aa upon opposite sides, and with the part b upon one side of said ribs of less Width and greater thickness than the part c upon the other side of the ribs, the complete widthof the bar being equal to the length of the key-blank to be produced, and the'bar being specially adapted for cutting key-blanks therefrom, with the ribs of the bar running transversely to the length of the 9o key-blank, substantially as described, and for the purpose specified.

HUBERT C. HART.

Witnesses CARLOS L. MASON, J. L. DENISON.

Only a few operations are re- 7o 

